Custodians:

Trees

Aaron Yukich

Black Oak (Quercus velutina)

In the savannah areas of High Park the predominant tree is the Black Oak. This medium sized tree likes to grow on the dry uplands and at the top of ridges in well-drained sandy soil. Black oaks grow to 50-80ft or 15-24m and have an open spreading crown. The leaves are elliptical with 7-9 lobes which are either shallow or deep and narrow ending in a few bristle-tipped teeth. The leaves are yellow-green with brown hairs below and shiny green on top and in the fall they turn a brown or a dull red. The bark is dark gray on the outside and the inner bark is yellow or orange. The inner bark used to be a source of medicine, tannin and yellow dye for cloth.

"The Black Oak was once called the Yellow-bark Oak for its inner bark is a bright orange-yellow. This layer of bark can be used fresh or dried and pounded to a powder to produce a yellow dye."

The average life expectancy of the Black Oak is 150-200 years, this is less than the Red Oak which is 250-300 years, and White Oak which is 500 or more.

The scientific name of the Black Oak "velutina" derives from the velvety surface of the shoot, leaf, and leafstalk. The fuzz on the upper side of the leaf falls off, leaving it stiff and parchment-like. This leaf-coating helps to minimize moisture loss through transpiration.

The Toronto area is the northern limit of black oak.

Eastern White Pine (Pinus strobus)

This tree has a very wide range in Canada, including High Park. White pines are found anywhere from southeast Manitoba to Newfoundland. Eastern white pines can grow to a height of 33 m (100 ft.) with a diameter of 0.9-1.2 m (3-4 ft.) and thrive best in sandy, well-drained soils. Needles grow in slender, blue-green bundles, 6-13 cm (2.5-5 in) long. Cones are a yellow-brown colour, narrow and cylindrical in shape. The cone scales are thin, rounded and flat. Bark is typically grey and becomes rough and thick over many years of growth. At one time, Eastern white pines were the most valuable tree in the northeast, commonly used in construction. The tall, straight trunks made perfect masts for ships during the colonial period.

Black Ash (Fraxinus nigra)

Also known as the “basket ash” or the “hoop ash,” this tree also grows in many places across Canada in a range very similar to the Eastern white pine – southeast Manitoba to Newfoundland. The Black ash grows to a height of 9-15 m (30-50 ft.) and has a diameter of approximately 0.3 m (1 ft.).

Black ashes grow best in wet soils, and particularly prefer cold, poorly drained swamps. They also grow in conifer or hardwood forests. The leaves are broadly lance-shaped, have a fine, saw-tooth edge and no stalk. They are dark green on top and have rust-coloured hairs along the mid-vein on the bottom. They turn brown in autumn. This tree produces both flowers and fruit. The flowers are long and purplish in colour, growing in small clusters. The fruit is a 2.5-4 cm (1-1.5 in.) key which matures late in summer. The Black ash derives its nicknames from traditional uses of its wood to make baskets, barrel hoops and woven chair bottoms.

Honeylocust (Gleditsia triancanthos)

In Canada, the Honeylocust is found only in the southernmost parts of Ontario. It stretches up to a height of approximately 24 m (80 ft.) and reaches a diameter of 0.8 m (2.5 ft.).

Honeylocusts grow well in mixed forests, preferring the moist soils found in river floodplains. The leaves of the Honeylocust are a shiny green colour on top with fine wavy edges, paired with no stalk. The underside is a dull yellow-green colour and the leaves turn yellow in autumn. The flowers are a greenish-yellow colour and covered in fine hairs. They are bell-shaped with five petals each. The fruit of the Honeylocust is a 15-41 cm (6-16 in.) wide, flat pod. These pods shed unopened late in the fall and inside is many dark brown seeds in an edible pulp.

Black locust Robinia pseudoacacia, which is native to the southern Appalachians and the Ozarks, also occurs in High Park. READ MORE

Catalpa (Catalpa speciosa)

The catalpa is a tree with a rounded crown of spreading branches. The leaves are broad and heart-shaped, dull green in colour which darkens to a blackish colour in the fall. The tree bears long, cylindrical brown fruit that resembles a cigar or a bean. The fruit matures in autumn, but remains attached in winter. The purple-spotted, orange-striped white flowers of the tree stand in branched, upright clusters. They are approximately 5-6 cm (2-2 ¼ in.) long and appear in late spring. Catalpas grow to a height of 15-24 m (50-80 ft) and can be found in naturalized open areas such as roadsides and clearings, as well as in moist valley soils by streams. This tree is native to Ontario but not indigenous to High Park. It has been found in the northeast corner of the park near the Forest School.

National Audubon Society. 1980. Field Guide to Trees, Eastern Region.
Alfred A. Knopf, Publisher. Random House of Canada, Canadian Publisher.

A Mast Year for Oaks

Some tree seeds such as acorns provide a good food source for many animals such as squirrels and blue jays. If the trees provided level acorn production every year, such animals would eat most of them and leave too few to germinate new trees. The trees get around this problem by producing few acorns for about four years and then a bumper crop (known as a "mast year"). There are not enough foragers to eat all the acorns in a bumper crop and the next year there are not enough acorns to support a large population of foragers. The mechanism by which all the trees within a region coordinate their mast years is poorly understood.

PHOTOS:Most of our site's photos were contributed by local photographers and taken in High Park. Please do not copy or reproduce them without permission. To contribute photos (low resolution), contact mail@highparknature.org